An interesting avenue for future work is to calculate the temperature dependence of the in-plane magnetization \(M(H_x)\)  up to the respective \(T_{\rm N}\)  of EuMg\(_2\) Sb\(_2\)  and EuMg\(_2\) Bi\(_2\)  for comparison with the corresponding data in Refs. [1]}, [2]}. Another avenue is to investigate the low \(ab\) -plane field behavior of A-type-antiferromagnets with a layered tetragonal Eu structure and with the ordered moments in the \(ab\)  plane which would have twofold in-plane anisotropy instead of the threefold trigonal in-plane anisotropy in EuMg\(_2\) Sb\(_2\)  and EuMg\(_2\) Bi\(_2\) .
